摘要:

Basic concepts of climate modeling are reviewed. Starting with a simple energy‐balance model, problems associated with calculating the greenhouse effect are introduced. Radiation transfer calculations in multi‐year models and the contributions of water vapor and clouds in the greenhouse effect are discussed. (AIP)

ISSN:0094-243X    

DOI:10.1063/1.41928

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The physical basis of global climate models is reviewed, with emphasis on the atmospheric sub‐model. An introductory discussion of the physics of the climate system is followed by a description of the numerical methods and physical parameterizations that have been developed for climate modeling. Current issues in model development are highlighted, and future directions are briefly discussed.

ISSN:0094-243X    

DOI:10.1063/1.41932

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Radiative forcing of Earth’s climate due to increases in greenhouse gases is compared in a number of Geneal Circulation Models. Feedback effects due to water vapor and clouds are discussed. (AIP)

ISSN:0094-243X    

DOI:10.1063/1.41921

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Results obtained by a NASA multisatellite experiment on the balance of solar radiation and thermal radiation in the atmosphere are presented. The role of radiative—convective—dynanic interactions in producing climate change is discussed. The importance of measuring the feedback between clouds and climate is pointed out. (AIP)

ISSN:0094-243X    

DOI:10.1063/1.41922

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Instrumental measurements of air and sea temperature and of sea level are rarely more than a century in length, and are characterized by numerous observational inconsistencies. Truly ‘‘global’’ data sets do not exist, except from satellite measurements during the last decade, primarily because most of the 71% of Earth’s surface covered by the oceans is not sampled. Surface air land temperature records are plagued by changes in measurement techniques, location of thermometers, and microclimate changes, notably urbanization. Surface marine air temperature too are affected by changing ship design, height of thermometers, and particularly daytime biases. Sea surface temperature data have similar difficulties plus the added problems of changed ship routes, and shifting from bucket to engine intake observations. Sea levels from coastal tide gauges have notably shorter record‐lengths than temperature records, and often are dominated by diastrophism and subsidence at the lowest frequencies. Determining statistically significant climatic trends in any of these geophysical time‐series leads to uncertain results due to natural variability such as El Nin˜o‐Southern Oscillation events.

ISSN:0094-243X    

DOI:10.1063/1.41923

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

This paper first describes the nature of short term variability of the coupled atmosphere‐ocean‐biosphere system as shown by analysis and diagnosis of observations during the past 100 years. By ‘‘short term’’ we mean those fluctuations of the coupled climate system whose time scales range from 10 days to 1000 days. We have deliberately excluded any discussion of short range weather forecasting (less than 10 days) and decadal changes (more than 1000 days).

ISSN:0094-243X    

DOI:10.1063/1.41924

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Transport of deep water between the Atlantic, the Indian and the Pacific Ocean is described in terms of the ‘Great Conveyor Belt’ concept. Evidence from traces studies using radiocarbon, tritium and phosphates is presented. A hostory of deep water circulation and its impact on earth’s climante is given. (AIP)

ISSN:0094-243X    

DOI:10.1063/1.41925

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

This paper summarizes the atmospheric cycles of carbon dioxide, methane, halocarbons and nitrous oxide. The emission sources and rates of change in the concentration of thee radiatively active trace gases are discussed.

ISSN:0094-243X    

DOI:10.1063/1.41926

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Atmospheric carbon dioxide levels are controlled over long time scales by the transfer of carbon between the atmosphere, oceans, and sedimentary rocks— a process referred to as the CO2geochemical cycle. Carbon dioxide is injected into the atmosphere‐ocean system by volcanism; it is removed by the weathering of silicate rocks on the continents followed by the deposition of carbonate minerals on the sea floor. Humans are currently perturbing the natural carbon cycle by burning fossil fuels and deforesting the tropics, both of which add CO2to the atmosphere. The effects of human activities on future atmospheric CO2levels can be estimated by including anthropogenic emissions in a model of the long‐term carbon cycle. The model predicts that CO2concentrtions could increase by a factor of six or more during the next few centuries if we consume all of the available fossil fuels. Preserving existing forests and/or reforesting parts of the planet could mitigate the CO2increase to some extent, but cannot be depended on to make a significant difference. Because the removal processes for atomspheric CO2are slow, the maximum CO2level reached is relatively insensitive to the fossil fuel burning rate unless the burning rate is many times smaller than its present value. The model also predicts that hundreds of thousand of years could pass before atmospheric CO2returns to its original preindustral level. Implications of these results for future energy and land use policies are discussed.

ISSN:0094-243X    

DOI:10.1063/1.41927

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The potential for biotically mitigating global warming is receiving a great deal of policy and technical attention around the world. Elements of the political community are drawn to the notion that land‐use patterns can be modified more easily than energy consumption patterns, and some modelers suggest that the potential for storing carbon in terrestrial ecosystems is very large. Most work to date, however, uses only physical criteria in estimating how much land might be available for reforestation. Accounting for social and economic constraints is much more difficult, resulting in daunting uncertainty about what could actually be accomplished. Furthermore, our relative ignorance of the functioning of the global carbon cycle makes attempting to manipulate it for human purposes questionable at best. Nevertheless, there are many reasons besides global warming to pursue a radical restructuring of land‐use patterns around the world. Such a restructuring should be undertaken in conjunction with many other measures to slow global warming, most immediately in the energy sector.

ISSN:0094-243X    

DOI:10.1063/1.41929

出版商:AIP    

年代:1992

数据来源: AIP